Note: Descriptions are shown in the official language in which they were submitted.
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ENERGY-DIFFERENTIAL MICROWAVEABLE FOOD PACKAGE
FOA
[0001] This disclosure relates generally to an energy-differential
microwavable food
package, and in par6cu{ar to a food package for differential energy input to
two different
food products both contained within the same food package.
8ackground
[0002] Two or more different food items are often packaged together in the
same
container and then frozen, refrigerated or shelf-stabilized before use. The
frozen food
package can then be reheated in a microwave to thaw the food items and bring
them to a
preferred consumption temperature. Different frozen, refrigerated or shelf-
stable foods that
are packaged together often require different energies, or differential energy
inputs, to
reheat the food items in the microwave prior to consumption. However, despite
this
differential in energy requirements for heating, the foods often are placed in
the microwave
oven and cooked together for the same amount of time, which can result in one
or more
food items being overcooked or undercooked.
[0003] Often the first and second food products have different energy
requirements
when cooking or heating, such that if both food products are placed in a
microwave for the
same amount of time at least one food product may be overcooked while the
other may be
undercooked. For example, if stored in a frozen condition, one food product
may thaw
faster than another food product and once thawed that food product continues
to cook and
receive more energy, and thus cook faster than the other food product,
resulting in non-
uniform cooking of the two food products. To solve this problem where two or
more
different food items are to be simultaneousiy heated in a microwave and one
food item
requires more heat than another food item, a shielding and/or susceptor
material has been
applied to generally rigid packaging, such as paperboard trays, thermoforrned
containers
and the like.
[00041 When a frozen. refrigerated or shelf-stable food product like a
sandwich is to
be reheated in a microwave where the multiple food items make up the whole of
the
product, it can be desirable to obtain different temperatures. One such
attempt to heat a
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sandwich product is disclosed in U.S. Patent No. 5,416,305, where a package
for a
sandwich separates the bread from the non-bread (i.e., the filGngs of a
sandwich) portion so
that upon reheating the frozen sandwich, the non-bread container can be
removed to allow
only heating of the bread component. This can create two heating steps if the
non-bread
component is also required to be heated, as well as requiring a further step
to reheat the
bread component if it has cooled off while heafing the non-bread component.
[0005] Multi-component containers are known that store two or more different
food
items and allow for sections of the container to be exposed to microwave
energy while
shielding other sections from the microwave energy, where the different
sections
correspond to the different food requirements. Various shielding techniques
are known that
shield or prevent microwave energy from heating one food item, while allowing
microwave
energy to heat another food item in the same package. In U.S. Patent No.
5,416,304, one
such shielding apparatus is used with a frozen pizza, where the shield is in
the shape of a
ring and is wrapped around the periphery of the pizza to help provide an
improved
uniformity of cooking, whereas without the shield the crust could possibly
overcook, since it
thaws before the rest of the pizza and then continues to absorb energy at a
higher rate than
the rest of the frozen pizza. Another shielding technique is disclosed in U.S.
Patent No.
4,874,618, where a shield shaped like a sleeve fits around a cup-like
container which
contains ice cream and a sauce or other food item to be warmed or heated. The
sleeve is
fitted such that it only shields the ice cream part of the container during
microwave heabng,
keeping the ice cream frozen while allowing the sauce or other food item to be
heated.
Another similar ice cream container is disclosed in U.S. Patent No. 4,934,829,
where a
container with an ice cream and a food item to be heated is wrapped along the
outside of
the container with a shield, such as aluminum foil. The foil wrapping covers
the top and
sides, stopping just short of the bottom of the container where the food item
to be heated is
located, thus allowing the bottom portion to be heated while keeping the ice
cream from
being heated. In each of these examples, though, the generally rigid packaging
can
disadvantageously add to the costs, as well as limit the shapes and
configurations available
for the packaging. Moreover, there can be additional costs associated with
attaching the
shielding to the rigid packaging, such as when performed using in-mold
labeling.
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[0006] There are other multi-component containers that can contain a susceptor
zone, which is a zone that absorbs microwave energy, or both a susceptor zone
and a
shielding zone. U.S. Patent No. 6,903,320 discloses a multi-component molded
microwaveable container having at least two sections, where at least one
section has a
susceptor zone. This container can similarly be used for an ice cream food
product and a
cake or sauce. The container can also include a shielding zone.
[0007] Paperboard or other generally rigid containers or trays have several
disadvantages. Such containers or trays can be costly. Also, they can have
limitations on
the sizes and shapes into which it can be configured. Further, different
configurations can
require different tooling, and not be readily adjustable to accommodate
differently-shaped
products.
Summarv
[0008] An energy-differential microwaveable food package is provided that
addresses the aforementioned disadvantages of the prior art. Instead of having
a shielding
layer disposed on a generally rigid compartment or on a generally rigid tray
disposed within
an outer packaging, shielding for at least one of the two different food
products is provided
on an outer film wrapper. This. advantageously can -reduce the costs of
packaging by
eliminating a requirement for additional outer packaging, as well as a
requirement for rigid
packaging having shielding thereon. Further, the flexible film can be readily
adapted to the
desired size of the food products, and can also be adapted, such as by
trimming, to
accommodate differently-sized products.
[0009] In one aspect, a temperature-differential microwaveable food package is
provided that contains at least two different food products, including a first
food product and
a second food product different from the first food product. A common flexible
film wrapper
surrounds the first and second food products. The film wrapper has a microwave-
influencing segment, such as a microwave shielding material, posifioned
adjacent the first
food product and spaced from the second food product such that there is a
temperature
differential between the first and second microwave food products following
microwave
heating in the film wrapper.
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[00010] In another aspect, a method is provided for packaging at least two
different
food products in a temperature-differential microwave package. The method may
include
providing a first food product and a second food product different from the
first food
product. The method may further include positioning a microwave-influencing
segment of a
common flexible film wrapper adjacent the first food product and spaced from
the second
food product such that the segment results in a temperature differential
between the first
and second microwave food products foliowing microwave heating. The method may
also
include sealing the first and second food products in the film wrapper.
[00011] In another aspect, a method is provided for microwave heating a first
and
second food product. The method may include placing a package having an outer
fiexibie
film wrapper containing separate first and second food products in a microwave
oven,
heating the first and second food products together in the microwave oven
while the first
and second food products are disposed in the film wrapper, and limiting the
microwave
heating of the first food product to a different degree than the second food
product during
heating of the first and second food products together in the microwave oven
at least In part
using the film wrapper.
[00012] One or both of the 'first and second food products may optionally be
supported by a rigid support disposed in the film wrapper. The rigid support
may have feet
to elevate the support above the bottom of a microwave oven.
8rief Descriation of the Drawinos
(00013] FIGURE 1 is a perspective view of an outer film wrapper containing two
different food products;
[00014] FIGURE 2 is a section view taken along line 2-2 of FIGURE 1 and
showing
both a shielded region of the outer film wrapper adjacent one of the food
products and a
non-shielded region of the outer film wrapper adjacent the other of the food
products;
[00015] FIGURE 3 is a perspecdve view of an outer film wrapper containing a
tray
which is supporting two different food products;
[00016] FIGURE 4 is a section view taken along line 4-4 of FIGURE 3 and
showing
both a shielded region of the outer film wrapper adjacent one of the food
products and a
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non-shielded region of the outer film wrapper adjacent the other of the food
products, as
well as the tray supporting the two food products;
[00017] FIGURE 5 is a detailed section view of region V of FIGURE 4, showing
details
of the construction of the shielded region of the outer film wrapper; and
[00018] FIGURE 6 is a detailed section view similar to that illustrated in
FIGURE 5,
but showing an alternative construction of the shielded region of the outer
film wrapper.
Detailed Description of the Drawinas
[00019] The food package illustrated in FIGURES 1-6 and described herein
includes
two different food products disposed within a common flexible film wrapper. A
portion of
the flexible film wrapper adjacent a first of the food products is adapted to
at least partiaiiy
shield microwave radiation from heating the first food product to the same
degree as the
second food product is heated when both are heated together in the film
wrapper in a
microwave oven. This advantageously permits the film wrapper and the first and
second
food products to be placed in a microwave oven for the same time period, but
can reduce
the microwave energy input to one of the food products to a different degree
than the other
of the food products.. The use of the flexible film wrapper eliminates the
need for additional
outer packaging, as well as reduces the costs associated with providing
generally rigid
packaging having the shielding thereoin. Also, it can be more cost-effective
to adjust the
size of the film, such as by trimming excess film, to accommodate different
product shapes
than having to create tooling for differently-shaped rigid packaging. Afthough
such outer
packaging and rigid packaging are not necessary, they may nonetheless be used
with the
food package described herein.
[00020] The food package 10 of the first exemplary embodiment has a flexible
film
wrapper 20 which encloses a first food product 12 and a second food product
14, as
illustrated in FIGURES 1 and 2. The film wrapper 20 includes a microwave
shielding layer
28 adjacent the first food product 12 but not adjacent the second food product
14, as
illustrated in FIGURE 2. During microwave heating of the food products 12 and
14 together
in the film wrapper 20, the shielding adjacent the first food product 12 wili
at least partially
restrict microwave radiation from heating the first food product 12 to the
same degree as
the second food product 14. Thus, both food products 12 and 14 may be heated
together
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in the film wrapper 20 in a microwave oven for the same period of time, with
the first food
product 12 receiving a different microwave energy input than the second food
product 14.
[00021] The food package 110 of the second exemplary embodiment has a first
food
product 12 and a second food product 14 with are supported by a generally
rigid tray 140,
as illustrated in FIGURE 3. The film wrapper 120 includes a microwave
shielding layer 128
adjacent the first food product but not adjacent the second food product 14,
as illustrated in
FIGURE 4. As in the first embodiment, the shielding adjacent the first food
product 12 will
at least partially restrict microwave radiation from reaching the first food
product 12 to the
same degree as the second food product. This can permit both food products 12
and 14 to
be heated together in the film wrapper 120 in a microwave oven for the same
period of
time, with the first food product 12 having received a different energy input
following
microwave heating as compared to the second food product 14.
1000221 The microwave shielding layer 28 and 128 may be integrally formed with
the
wrapper 20, or may be separately applied. As shown in FIGURE 5, the shielding
layer 28
may comprise a laminate having an outer and an inner protective sheet 34 and
30 with a
shielding sheet 32 disposed therebetween. The outer sheet 34 may be adhered to
the
inner surface of the wrapper 20. Alternatively, as shown in FIGURE 6, the
shielding layer
28 may comprise a laminate having an inner protective sheet 30 and a shielding
sheet 32
attached to the inner surface of the wrapper 20. = The sheet 30 (Figure 6) or
sheets 30 and
34 together (Figure 5) may cover any otherwise exposed edges of the shielding
sheet 32.
Moreover, the laminate shielding alone may be applied to the outerwardly-
facing surface of
of the film instead of the illustrated inwardly-facing surface. The shielding
layer can also be
applied using deposition techniques, such as printing or spraying. Other
permutations can
also be used. Types of suitabie shieiding are disciosed in PCT publications
1IV02005/068321 and W02003/043474, the disclosures of which are hereby
incorporated
by reference in their entireties. The outer wrapper 20 can be in the form of
flow wrap, a
bag, or a sleeve, although other flexible configurations can be used. Further,
the outer
wrapper 20 may be formed of a laminate having an inner heat sealing layer to
facilitate
seaGng of the outer wrapper 20 to itself in order to form a sealed package. In
one example,
the heat sealing layer of the outer wrapper 20 may be the inner protective
sheet 30 for at
least one of the seals of the outer wrapper 20. That is, the heat sealing
layer of the outer
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wrapper 20 may be sealed, such as an end seal, to the inner protective sheet
30 having
heat sealing properties.
[00023] By way of example, the film of the outer wrapper may be formed from
polypropylene, polyethylene teraphalate, or other materiais suitabie for
contact with food
and microwaving. The shielding layer may include aluminum or other shielding
metals.
When a laminate is used, the laminate layers may include the same materiais as
the film,
and could also be ethylene vinyl alcohol polymer or polyethylene.
[00024] The film forming the wrapper 20 and 120 has the microwave shielding
layer
28 and 128 positioned adjacent the first food product 12. Although depicted as
being only
adjacent the first food product 12 in FIGURES 1-4, the shielding layer may be
adjacent
both food products 12 and 14, with a iesser degree of shielding adjacent one
of the food
products as compared to adjacent the other. For example, the shielding layer
may have
perforations or other patterns and/or decreased thickness adjacent the one of
the food
products requiring less microwave heating as compared to the other of the food
products.
[00025] The film wrapper 20 may be the only outer packaging, or other outer
packaging may also be provided in addition to the film wrapper 20. The film
wrapper 20
has a seal 22 about its periphery to endose the two food products 12 and 14.
An easy-
open feature, such as a thinned die line, a score line, or another area of
weakness, as well
as an aligned starter notch, may be provided to permit the consumer to readily
open the
film wrapper 20 to gain access to the food products 12 and 14. The film
wrapper 20 may
be opened prior to microwave heating to pemnit venting and restrict the buiid-
uP of gasses
within the sealed wrapper 20, and/or a pressure reiieving vent (such as a one-
way valve)
may be provided to permit venting during and after microwave heating.
[000261 Turning now to details regarding the tray 140 of the second exemplary
embodiment, illustrated in FIGURES 3 and 4, the tray 140 includes a food
product support
surface 142 elevated using muitiple legs 146. An opening 144 may optionally be
provide
for receiving the lidded cup 16 containing the second food product 14. A
susceptor surface
(not shown) may also be provided on the food product support surface 142 for
browning
and/or crisping of the adjacent surface of the food product(s). The legs 146
can
advantageously elevate the food product 14 to permit microwave radiation to
reflect off of
the bottom wall of a microwave oven and onto the bottom surface of the food
product 14 for
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additional microwave heating. In one example, the shielding layer 128 may be
absent or
reduced from beneath the first food product 12 as compared to above the first
food product
12. This, in combination with the elevated food product support surface 142,
can be used
to heat one side of the first food product 12 a greater degree than the other
side. The
generally rigid tray, which may be formed of paperboard, plastic or the like,
can facilitate
handling of the food products, particularly following microwave heating.
[00027] The first and second food products are preferably, though not
necessarily,
different from each other. They may be frozen, shelf-stable or refrigerated.
In the
illustrated example, the first food product 12 is a sandwich and the second
food product 14
is a liquid food product, such as a soup disposed in a lidded cup 16. The
second food
product 14 may tend to require a greater amount of energy compared to the
first food
product 12 to bring each product from its initial state to the desired heated
states, for
example. Therefore, little or no shielding adjacent the second food product is
necessary to
provide the desired cooking results of the first food product. The first food
product 12 can
comprise a non-liquid food product, such as a bread-based food product like a
sandwich,
that tends to require a lesser amount of energy to bring the bread and its
fillings from a
frozen state to that of a preferable warm temperature for consumption. As a
result, less
microwave energy is needed, thus nrquiring shielding or a greater degree of
shielding
adjacent the first food product 12 as compared to the second food product 14
to prevent or
n:strict the same amount of microwave radiation from heating the first food
product 12.
[00028] The food products that can be contained in the package 10 may all
initially be
in a frozen, refrigerated, or shelf-stable state, but can be heated to any
state preferable for
consumption. For example, food products can be consumed in a liquid state
(i.e., melted or
thawed in the container) or can even remain in a relatively frozen state after
heating, for
consumption. Possible food products may include combinations as crackers and
cheese
dip, different types of nuts which require different energy inputs, popcom and
soy nuts, a
soup and a sandwich, a brownie and a whipped cream, a brownie and ice cream,
chili with
cheese and sour cream, soup and uncooked bread, sandwich and cottage cheese,
vegetables and entrees (such as chicken breast, pasta, etc.), dipping sauce
and pizza,
macaroni and cheese, cooked bun and hot dog, and foods such as caramel or
chocolate in
cookies, and a grilled cheese sandwich.
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[00029] To heat the two different food products 12 and 14 using a microwave
oven,
the food package 10 or 110 containing the first and second food products 12
and 14 can be
placed in a microwave oven. The food package 10 or 110 can optionaliy be
opened for
venting. The microwave oven can then be operated for a preselected time period
to heat
the first and second food products 12 and 14. Due to the adjacent shielding
layer, the first
food product 12 wil{ not be exposed to the same amount of microwave radiation
as the
second food product 14, resulting in a different energy inputs to the first
and second food
products 12 and 14 during heating in the microwave oven. For instance, the
first food
product 12 may not be heated the same amount as the second food product 14. In
the
example where the first food product 12 is a frozen sandwich and the second
food product
14 is a frozen soup, following microwave heating the frozen soup can be thawed
into a
heated liquid, while the frozen sandwich can also be thawed but not heated the
same
amount as the soup. Following microwave heating, the package 10 or 110 can be
removed
from the microwave oven, the film wrapper 20 or 120 opened (if not already
opened or not
fully opened), and the first and second food products 12 and 14 removed
therefrom for
consumption. tf the tray 140 is present, then it can be used to remove the
first and second
food products 12 'and 14 from the film wrapper 120.
[00030] From the foregoing, it will be appreciated a microwaveable food
package is
provided that allows for temperature differential microwave heating of at
least two different
food products contained within a common flexible film wrapper. However, the
disclosure is
not limited to the aspects and embodiments described hereinabove, or to any
particular
embodiments. Various modifications to the microwaveable food packages
described
herein can result in substantially the same food package.
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